kuehn



July 7, 1931. G. F. KUEHN 9 MAGNETO BREAKER ADJUSTMENT Filed Dec. 19. 1929 s Sheets-Sheet 1 INVENTOR GEORGE F. KUEHN 9 his attorneys July 7,1931. G. F. KUEHN 1,813,809

IAGNETO BREAKER ADJUSTMENT Filed Dec. 19, 1929 3 Sheets-Sheet 2 I VENTOR RGE F. KUEHN 3y kzls aZ-Zar-neys July 7, 1931. a. F. KUEHN IAGNETO BREAKER ADJUSTMENT Filed Dec. 19, 1929 3 Sheets-Sheet 3 Patented July 7, 1931 STAT EIS OFFICE GEORGE E. KUEHN, or mcxson; nsmms; m'w'y nx; s'ssisnoie' To nz's'nfmsu'n MAGNETO CORPORATION, or NEW YORK, N. Y., A CORPORATION or NEw'Yoiz'K MAGNE-ffi BREAKER: Amtrsrrsm-NT Application filed December 19; 19292 Serial in. 415,254;

This im ention deals witha br'caker mechanism for a K133316110 its" principzii concern being 'withthe provision for setting or for adjusting within set limits the point at whichthebreakoccurs inrelzition to the' position ofthe armature with respect to the magnet It provides a simplified arrangenientof theparts which have to do with this setting and adjustment making it possi 16 bleto'haveapermuhent setti-ng ora variable;

one ,'-f or rotationin' either direction, and it simplifies the whole breaker assemblyby givirrg to one part'th'e' doublefunction' of' being he breaker housing and the breaker cum. 115 The range orm-iazimmetthe cam settin'g is .:onsiclerable and manydifle'rent settings'are ossible, thus making the operlition of the magneto more 'eflicient'bee'ause o'fthe ability to set the bi'etik point 1 p'reci'se'ly.

In the accompanying "drawings F'gure" lis a vie-win section of -a-magmeto in which the-"inventive ideas here disclosed are embodied.

F igure"2 is a fragmentary View, partly schematic; showing the relation between the ar1'i1ature,'the poles, thebreaker cam and the breaker cam follower, together with the 'p'ro-' vision for setting the range of adjustmentof the' break point. p

Figure Sis a similar view but with the breaker mechanism showniii end elevation and i the adjustment limiting devices" shown in section.

Figure 4 is an endview of'the member which serves as a housing. for the breaker mechanism and hasacam surface for actuating-the breaker. I

Figure 5 is a side View of the same member with a part shown iii-section about on" the line 5-5 of Figured I I Figures 6 to 10 inclusive are like fragn'ientary views of the construction by means of which either a-fixed breakpoint-or the limits ofyariation of the breakpoint are set,

the several views showing different settings.

Figure 11' is a partial view in section through the armature core and the bottom of the casing, illustrating the use of a' setting age;

The magnetohas a main part lfiforniirigthe casing for the end ofthe armaturethat carries the coils 16"and for the large gear-'17- thatturns the distributor arm 18'. Thegear 17 is mounted on'a-spindle supported'ina hearing 19 that-is received in a'n'openinglin the upper pia'rtQO of the-casingsection 15' within the loop of the magnetQL; Tl'ie "lower part of the main casing section 15 has-a re cess for a hearing 22 that supports oneend-o'f the armaturespindle 23,

Asccond casing section 25 fits the rim'of the open end of the main section 15--and*is held thereto by screws 26. This secondsection has an opening 27 in an inward flange that has a fiat outer face atthc rim'of theopening, and again'stthis face rests the dis tributor cup 28 held by screws "29; Belowthis relativelylarge opening is a smaller one 88 whichreceives a member that supports the breaker housing and. also abeari'ng for the end of the arn-i'ature shaft. The latter extends through to the breaker housing where it carries the rotating parts of the breaker mechanism as described more fully hereinafter.

A conductive ring 31 mounted on an insulating' body turning with the armature spindle and suitably connected electrically with the secondary coil of the armature-,-rota'tes in contactwith a spring-pressed carbon brush 32 mounted in a laterally extending. arm-33 of-the distributor cap 28. The cap is of molded insulatingmaterial.-- This brush is 'conductively connected, through the interior of the distributor cap 28, with a" center inwardlyextending brush '34 which is mounted in a'central nipple 39 and bears against that part of a conductive piece 35 on the distributor arm that is on the axis of the fibre gear 17. The end of this conductive piece turns with the'distrihutor arm ina circle such that it-justclearsthe'elect-rodes or terminal pieces 36 which areon the inner-ends of the nipples 37 integral with the distributor cap. These nipples are arranged-in a cir-' cular series and register with the exterior bosses 38 on the cap which receive the ends of the cables'leading to the spark plugs. In theinterior of the nipples are suitable provi sions for connecting the cables electrically to the terminal pieces 36. The construction and advantages of this distributor part of the magneto are described more fully in my application Serial No. 415,285 filed herewith.

In accordance with usual practice, the primary and secondary coils are connected in series, one forming a continuation of the other, and the other end of the primary coil is connected to the armature casing as a ound. The other end of the secondary coil is connected to the slip ring 31 as shown, by reason of which the high tension current may flow to the distributor; The end of the sec ondary coil which is connected to the live end of the primary is also connected with one side of a condenser, thus putting the primary coil and the condenser in parallel, and to one side of the breaker, the other sides of the condenser and breaker being grounded.

The breaker mechanism is at the end of the armature shaft and is held thereto by a lon screw 80-which threads into a member 81 that is secured within an insulating sleeve 82 set in a counterbore in the tubular member 83. This member 83 forms that end of the armature shaft, being secured by means of a flange 84 at its inner end to the core 126 of the armature. The tubular member 83 carries the insulating hub 67 on which is the slip ring 31. The distributor driving gear 83 is mounted next to the hub on this tubular member and, so that it may turn with it, it is held by screws 86 extending into the flanged end84 of this member. The outer end of this hollow member 83 is'divergent and extends into and slightly beyond the bearing 86 which is held in a recess in the inner face of a circular member 87 mounted in the opening 88 (mentioned above) in the casing section 25. This member 87 serves as the fixed base of the breaker housing.

' A disc or plate 89, received in a recess in the outer face of the base 87, has a rearward tapered extension 90 lying in the divergent endof the hollow extension 83 but clearing the screw 80. The disc 89 forms the base for the rotating breaker parts and turns with the armature and with the screw 80 although insulated from the latter by a sleeve 91 which serves also to maintain the spacing of the screw and the disc. A hollow boss 92 on the base disc 89 contains a spring pressed carbon brush 93 whichbears against the face ofthe circular fixed base 87. Also mounted on the disc 89 is a block 94, insulated therefrom by a collar 95 around the screw 96 which holds the block on the plate and by the sleeve 91, described above, together with a sheet of insulating material between the adjacent face of the disc and the block. The enlarged head 97 on the end of the screw 80 rests in a recess in the outer face of this block and is held from turning relatively to the block by a spanner piece 98 held to the block and engaging the faces of the hexagonal head (see Figures 1 and 3). The screw 80 thus holds the block 94 and the base disc 89, which are held together by the screw 96, against the hollow shaft member 83 so that all rotate with the armature. There is a running fit between the disc 89 and the fixed base member 87.

Extending through the block 94' transversely (Figure 3) is a screw 100 with a locking nut 101. One end of this screw serves as the fixed breaker point 102, adjustable in position by threading the screw in or out of the block. The movable breaker point 103 is at the end of one arm 104 of a bell crank having a circular recess at its pivot point enabling it to be set over a boss 105 on the base disc 89, thus giving a mounting pro-' viding for rocking on the disc. The other arm 106 of the lever has an end recess filled by a bearing piece 107 of fibrous material for engaging cams, yet to be described, which press the arm inwardly, and thusrock the V lever, twice in each revolution to separate the breaker points. A fiat spring'piece 108 is fixed to another boss 108 on the breaker disc 89 and its free end bears on the pivotal part of the bell crank lever to hold it on the boss 105. There is also a curved leaf spring 109 which is fixed at one end to a'lug on the block 94 and extends around the pivot of the bell crank breaker lever to the arm 106 thereof that carries the cam follower. The effect of this spring is to swing the arm 106 outwardly against the cams, thus pressing th breaker point The breaker points when in engagement complete a circuit from the center screw 80 to the magneto casing, thence to ground. This is a primary circuit since the inner end of the screw 80 is connected to a terminal 80 to which the live end of the primary coil is connected and the screw is otherwise insulated from the casing by the arrangement described.

The cams 110, 111 mentioned above for actuating the breaker are formed on opposite sides of the inner face of a ring member 112 (Figs. 1, 3, 4, 5) which is considerably wider than the cam faces and serves as a housing surrounding the breaker mechanism just described. It extends into an annular recess 113 (Figure 1) in the outer face of the circular.

103against the fixed point 102. p

parts of the ring, being shaped by'milling and grinding; The outer face of the part of the ring thatextends into the base piece has a recess 120 that extends something less than a quarter wayaround the ring and is so cut that its bottom surface lies on a chord of the ring circle or, as shown here, on two nearly parallel but intersecting chords 121, 122. The bottom surface co acts with screws 123, 124 (Figures 1, 2, 3, 610) extending into the recess from the under side through a part of the base member 87' that extends down through a-slot in the casing 25 at the rim of the opening 88. The reason for this extension is'that the material of the ring 87 is better suited to being'tapped than the casing material, through which the tapped holes would extend were it not for this extension, as in Figure 2. The purpose of this is to determine the single position of the ring 112 if it is to be fixed or to determine the limits of its movement angularly if it is to be adjustable. Positions of the ringare considered in relation to the position of the armature at the time the cam fol-lower first'engages either cam and is moved thereby to separate the breaker contacts 102, 103. The point at which that separation occurs is the break point.

Since the cam follower 107 turns with the armature and has a'definite position with respect thereto to bring the break point at approximately the right time, it follows that the position the armature core 126 occupies with respect to the poleshoes 125 at the moment that the break occurs depends on the position of the breaker cams 110, 111, and conversely, by moving the cam ring, the break point may be made to correspond to any given armature position. Likewise, since the distributor arm 18 turns in a geared relation to the armature and has a definite position corresponding to the armature position at any instant, the position of the breaker cams determines the relation between the break and the position of the distributor arm with respect to the electrodes 36. Thus there is a correlation between armature position, distributor arm position and break point, and shifting the cams causes the break point to occur f: at different times with relation to the swing of" the armature core 126 past the po'leshoes and themovement of the distributor terminal 72 past a given electrode. The current in the primary at any instant while the circuit is 3 closed depends of course on the position of the armature coil, or in other words, of the core 126, in relation to the fixed poleshoes 125.

The fibre gear 17 carrying the distributor arm 18 makes one turn for every three revolutions of the armature and the latter makes one and a half turns for every engine rotation. This is the relation for a six cylinder, four cycle engine in which each cylinder fires every two revolutions. For other types of engine, the relation is different but this one type will serve as an illustration. It is to be understood that the armature is so connected with the engine that the distributor terminal 72 registers with-eachelectrode as the piston of the corresponding engine cylinder reaches a point usually toward the end'of its compression stroke, at which ignition is most effective ordinarily. The ring 112 is so arranged that when at one limit of its range of variation or in its fixed setting, either cam 110 or cam 111 swings the lever 106 and causes a separation of the points 102, 103, or in other Words, abreak, atthe instant when a piston-is at this point in its stroke and the distributor arm is opposite the corresponding electrode. Thecam ring is so set that this point, the point-whereat the break occurs with the distributor directly op: posite the electrode in question,-is the one at which the primary current is at-its maximum value. For this thereis a definite armature positionwhich is known-beforehand: That is the point therefore of greatest spark efliciency. hen the break occurs, a higher voltage is induced in the secondary andis conducted through the distributor to the engine.

If the ring be moved from this end position, the break occurs after the piston reaches the said point in its stroke and the spark is said to be retarded. If no change is desired in the time of break, the ring is fixed in position with the resultthatthe break always occurs when the piston is at the same point. \Vhat this point-shall be depends on the position in which the ring is fixed and preferably it is the point at which the maximum primary current occurs. T hetwo cams- 11.0, 111, diametrally opposite, are provided so that there willbe a break for every 180 of armature rotation, that is to say, for every of'distributor arm rotation, the reduction effected by the gears and17 being in the ratio of 3 to 1. This assumes a six cylinder engine. Thus the break occurs as the distributor arm is passing an electrode, for the electrodes are 60 apart, and three cylinders are fired on everyrotation of the engine crankshaft.

The point at which'to set the cam ring, so that the break will occur when the armature is in position to give a maximu-m'primary current, may be readily ascertained. From the design of the armature it is known of course at what angular position of the armature this maximum current occurs and a gage G may be provided which can be inserted through an opening 61 in the bottom of the magneto casing 15 and placed against one pole 125 (see Figure 11); Then the armature is turned until the edge of one poleshoe 126 rests against the gage. The gage is of such size that it locates the armature in the position for maximum current. Holdingthe armature in that position, the

person making the adjustment may then set the cam ring accurately in a posit-ion such that the cam follower 107 of the breaker mechanism is at the end of the cam first engaged (see Figure 2). That insures a separation of the breaker points every time the armature reaches that position or one 180 from it, there being the two cams.

To provide for a similar setting when the magneto is to turn in the opposite direction, there is a similar opening 60 on the other side of the center line. These openings are normally covered by a screen 51 as they have a part in the ventilation ofthe magneto as described in my application Serial No.

Y vide five holes 130, The screws have either fiat, rounded or tapered heads and different ones are most suitable for different positions of the ring, the object being to avoid having an engagement between locking surfaces 121, 122 and an edge of a screw. An engagement between flat surfaces is preferable.

In Figures 6 to inclusive, are represented several different arrangements of the two screws. In these views the line denoted A indicates the linethrough the centers of the cams 110, 111 and the line B represents the line midway between the fixed poles and parallel to their faces. In Figure 6, the cam ring 112 is fixed in a position which, for

counter-clockwise rotation of the armature,

puts the line A away from the center line B. This setting would be determined by use of the appropriate gage G as described above. The position of the ring can be set very precisely by slightly retracting one screw and advancing the other. When both screws engage the ring, further adjustment is impossible without moving the screws. It is the practice to seal over the tapped holes 130 so that a setting once made will not be changed by the unskilled user.

Figures 7, 8, 9 and 10 representdifferent setting which permit various ranges of adjustment effected by turning the ring manually. The screws are used in different holes, as will be noted by comparing Figures 6, 7 and 10, and in this way the desired differences in the permissive range of movement of the cam ring are obtained, the screws in each case having a practically flat surface engagement with the ring, thus insuring against cutting that would disturb the setting. In Figures 7,8, 9 and 10 the timing ranges are successively greater, being respectively and Not only are there variations in the extent of permissive movement, but there are differences in trol lever'may be connected (Figure 3).

The arm has a split yoke 136 surrounding the cam ring 112 and clamped against it by a screw 137 connecting the two parts of the yoke. The range of permitted movement of the ring depends both on which holes the screws are in and the extent to which they are inserted. Various arrangements are possible, as will be obvious, and by proper selections many very precise settings may be had. The range of permissive movement ma be limited to zero or to any desired nite amount. I

In setting the screws for a desired range of adjustment, one screw preferably is set first to put one limit at a point such that the break will occur with the armature in position for'maximum current. That setting is made with precision. Thenthe other limit may be set by simply moving the ring through an angle equal to the range desired and then setting another screw to prevent further movement. It is desirable to seal the holes 130 after such a setting, leaving the user the limited range of adjustment by means of the arm 135.

For opposite rotation, the settings are made in the same way but with the camcenter line A on the opposite side of the line B and by using the gage G on the opposite side, that is, in the opening 60. The provision of more than two tapped holes for the limit screws makes possible this adaptation to either direction of rotation while enabling a great variety of precise settings for either direction of rotation. v I

The arrangement by which themember 112, which has the cams on its inner surface, serves as a ring housing for the breaker mechanism is of advantage not only for its simplicity and ease of adjustment but by reason of its mounting in a circular groove in the base member 87. This mounting affords an effective seal preventing the admis sion of dust and fines and similarly with the mounting of the breaker cap on the outer edge of the ring. The ring edges may be ground and in co-action with the surfaces of the cap and the base groove are very effective for the purpose. 7 i H Furthermore, it will be noted that the groove 120, into which the limiting'screws 123, 124 extend, doesnot extend through the ring. There is for that reason no opening to the interior incident to the provision for adjustment as has been the case heretofore.

Those holes 130 that do not have screws in them, in any one setting, may be sealed over, although no considerable amount of the dust which might enter through them could pass the seal afforded by the inner edge of the ring in engagement with the base of the recess in which the ring rests.

A further feature of great utility is the knurling on the exterior of the ring 112. This ring is of hardened steel but the knurling is easily put on before the hardening. Then when an operating arm 135 is put on to permit the ring to be shifted, it is not necessary to provide interlocking parts on the part of the arm surrounding the ring. An inexpensive die cast arm, of softer material than the ring, is provided and when tightened on the ring by the screw 137 becomes locked thereon due to the biting of the knurling into the softer metal of the arm. Thus the arm is securely held from slipping about the ring.

I claim 1. In a magneto, a casing, a rotatable breaker mechanism and a member mounted on said casing to form a ring housing for said mechanism, said member having a cam on its inner surface for actuating said breaker mechanism and having a movement between limits to vary the point of actuation of the breaker mechanism and means adjustable to change the limits of the movement of said member.

2. In a magneto, a casing, a rotatable breaker mechanism, a member mounted with freedom for turning on said casing to form a ring housing around said mechanism, and a cam on the inner surface of said ring for actuating the breaker mechanism, said member being shiftable between limits to vary the point of actuation of the breaker mechanism and means adjustable to vary the limits of movement of said member in either direction.

3. In a magneto, a casing, a rotatable breaker mechanism, a ring member mounted on said casing around said mechanism with freedom for turning and a cam on the inner surface of said ring for actuating the breaker mechanism, together with a on p on the outer edge of said ring member, said ring member being shiftable between limits to vary the point of actuation of the breaker mechanism and means adjustable to vary the limits of movement of said member.

4. In a magneto, a casing, a rotatable breaker mechanism, a ring member mounted on said casing around said mechanism with freedom for turning, a cam on the inside of said ring for actuating said mechanism, and means for limiting the permissive angular movement of said ring member with espect to the casing, said limiting means being adjustable to vary the limits of movement of said member.

5. In a magneto, a casing, a rotatable breaker mechanism, a ring member mounted on said casing around said mechanism with freedom for turning, a cam on the inside of said ring for actuating said mechanism, and screws in said casing adapted to engage said ring at spaced points to limit its permissive angular movement with respect to the casing.

6. In a magneto, a casing, a rotatable breaker mechanism, a ring member mounted on said casing around said mechanism with freedom for turning, a cam on the inside of said ring for actuating said mechanism, said ring member having a flat portion on its outer side, and said casing having spaced screws engaging said portion to limit the pe missive angular movement of said ring member with respect to the casing.

7. In a magneto, a casing, a rotatable breaker mechanism, a ring member mounted on said casino around said mechanism with freedom for turning, a cam on the inside of said ring for actuating said mechanism, said casing having three or more tapped holes with screws in any two of them arranged to engage the ring member to limit its angular movement with respect to the casing.

8. In a magneto, a rotatable breaker mechanism, a cam member for actuating said mechanism on each rotation, said cam member being angularly adjustable about said mechanism, and a fixed casing having at least three similar tapped holes with screws in any two of them arranged to engage said cam member to limit its angular movement, said holes being so arranged that, by putting the screws in different holes, difi'crent timing ranges on fixed settings may be had.

9. In a magneto, a casing, a rotatable breaker mechanism, a circular recess in said casing, a shiftable ring member extending into said recess with one edge engaging the base thereof, said ring surrounding said breaker mechanism, and having a cap on its outer edge, whereby a sealed housing is provided for said breaker mechanism.

10. In a magneto, a casing, a "rotatable breaker mechanism, a ringmember mounted with freedom for turning on said casing but having a sealing engagement therewith, said member forming a housing around said breaker mechanism, a cam on the inner surface of said ring for actuating said mechanism, a cap for the outer end of said ring, and a groove in the outer face of said ring and extending part way around the ring, together with screws in said casing extending into said groove to limit the permissive movement of said ring.

11. In a magneto, a casing, a rotatable breaker mechanism, a ring member mounted with freedom for turning on said casing and having a cam on its inner face for actuating said breaker mechanism, said ring having a knurled portion on its outer surface, together with an arm for shifting said ring said am having a portion surrounding ring and-adapted to be tightened on said knurled portion, gagin the knurled portion material, for the purpose described.

12. In a magneto, a casing, a rotatable breaker mechanism, a closed ring member mounted on said casing around said mech- V anism with freedom for turning and a cam formed integral with said ring and projecting inwardly for actuating said breaker mechanism, said ring'being recessed on its periphery for engagement with limiting stops.

13. In a magneto, a casing, a rotatable breaker mechanism, a closed ring member mounted on said casing around said mechanism with freedom for turning, a cam' formed integral with said ring and projecting inwardly for actuating said breaker mechanism, said ring beingrecessed on its peripheiy for engagement with limiting stops and a justable limiting stops for said ring.

14. In a magneto, a casing, a rotatable breaker mechanism, a closed ring member mounted on said casing around said mechanism with freedom for turning, a cam formed integral with said ring and rojecting inwardly for actuating said reaker mechanism, said ring being recessed on its periphery for engagement with limiting stops and limiting stops for said ring adj ustable to eflect independent variation of each limit of movement of said ring.

In testimony whereof I have signed my name to this specification.

f GEORGE F. KUEHN.

the part of said arm en- 7 being of softer 

